Polypyrrole Actuators for Electronic Braille Pins

Polypyrrole (PPy) actuators are a type of low voltage conjugated polymer eleetromeeha-nical actuator that has been evaluated for possible use in an electronie Braille sereen [9]. PPy actuation occurs through an electrochemical process whereby small voltages ( 5 V) applied between two electrodes in an electrolyte cause the movement of ions and solvent between the polymer and the electrolyte [10]. This mass transfer is mainly responsible for the volume changes that occur and that produce useful deformations/forces. The actuation performance of PPy has been shown to vary depending on the type of dopant ion and electrolyte used (Table 13.2). Strains and strain rates are measured under different 

PPy formulation Electrolyte Maximum Actuation Strain (%) Peak Actuation Strain Rate (%/s) Reference 

Notes TBA tetrabutylammonium PFe hexafluorophosphate PC propylene carbonate DBS dodecyl benzene sulfonate TFSI bis(trifluoromethylsulfonyl)imlde. 

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